(1) Field of the Invention
The methods and systems described herein relate to remote powering of sensors, and more particularly to methods and systems for delivering power to a number of remote sensors utilizing inductive coupling between a planar primary coil and a plurality of sensor coils.
(2) Description of the Prior Art
Submarines and other vessels utilize large sensor arrays for detection of acoustic energy within the surrounding water. For proper sensing and detection, the arrays or grids of sensors are mounted on the external side of the hulls of the vessels. The sensors are embedded in an acoustic polymer material and are generally several inches above the hull. Current on-hull sensor arrays are powered from the interior of the vessel. Power connections to the inboard side of a vessel typically include large, heavy and expensive wiring harnesses.
The wiring harnesses can add significant weight to the vessel and each power connection from the harness to a sensor requires a penetration through the hull. The wiring harnesses and penetrations can add significantly to the costs of the vessel. Additionally, each penetration provides a source of possible leakage and may decrease the overall structural integrity of the hull.
What are therefore needed are methods and systems for delivering power to the sensors without the use of wired connections. Such methods and systems may save significant amounts of weight and costs in overall acoustic detection array systems by reducing or removing large, heavy cable harnesses currently used to deliver power to the outboard sensors.
Reliability may also be improved by not requiring a physical connection through the hull in order for a sensor to receive power.
One such method would involve the use of coils and inductive coupling to power sensors. In the prior art there are examples of the use of this technology on a very limited scale. U.S. Pat. No. 6,535,133 to Gohara et al, for “Vehicle slide door power supply apparatus and method of supplying power to vehicle slide door” (issued Mar. 18, 2003) teaches a power supply apparatus for supplying electric power from a vehicle body to a slide door slidable mounted on the vehicle body of a vehicle, the power supply apparatus comprising a primary coil provided to the vehicle body; a secondary coil provided to the slide door, wherein the primary and secondary coils can be brought into proximity to each other upon closing of the slide door to effect a mutual induction operation so as to supply the electric power; a temperature sensor provided in a vicinity of the primary coil; a primary coil control device which is connected to the temperature sensor, and stops excitation of the primary coil in accordance with the temperature of the primary coil or the vicinity of the primary coil detected by the temperature sensor, so as to interrupt a supply of the electric power to the slide door; a slide door-contained battery for supplying electric power to a load driver driving and controlling at least one load on the slide door at least when the slide door is opened or when the supply of the electric power to the slide door is interrupted; and charging means for charging the slide door-contained battery with the electric power supplied to the slide door through the secondary coil.
U.S. Pat. No. 6,535,133 is a very relevant example of prior art in that it discloses a method for using two very closely spaced coils of approximately equal size for power delivery over the short gap that exists in a closed automotive sliding door. The invention requires the two coils to be very close together in order to operate. In addition, it is merely a one-to-one power delivery method and is used to keep a door-mounted battery charged.
What is needed is an inductive coupling method on a much larger scale that can employ a single large planar primary coil inductively coupling electrical energy to a number of smaller co-planar sensor coils above it, where the distance between the plane of the primary coil and the plane of the sensor coils remains constant.